How to pass a dropdown UI value to an enum in another script?

You can convert the dropDown value to an enum, it's be something like this

 using UnityEngine;
 using UnityEngine.UI;
 
 public class GetDropDownValue : MonoBehaviour
 {
     public Dropdown dropdown;
 
     public enum DropDownSelection { A, B, C }
     public DropDownSelection selection;
 
     private void Awake()
     {
         dropdown.onValueChanged.AddListener(delegate { DropdownValueChanged(dropdown); });//Add listener to Event
     }
 
     void DropdownValueChanged(Dropdown change)
     {
         selection = (DropDownSelection)change.value; //Convert dropwdown value to enum
     }
 }

Edit: For populate a dropdown with an enum, you will need to use the "System" namespace to get acess to the "Enum" type, see:

 using System;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class DropDownPopulation : MonoBehaviour
 {
     public Dropdown dropdown;
 
     [System.Serializable]
     public enum FormatPresetType
     {
         RGB,
         CMYK
     }
     FormatPresetType formatPreset;
 
     private void Awake()
     {
         PopulateDropDownWithEnum(dropdown, formatPreset);
     }
 
     public static void PopulateDropDownWithEnum(Dropdown dropdown, Enum targetEnum)//You can populate any dropdown with any enum with this method
     {
         Type enumType = targetEnum.GetType();//Type of enum(FormatPresetType in my example)
         List<Dropdown.OptionData> newOptions = new List<Dropdown.OptionData>();
 
         for(int i = 0; i < Enum.GetNames(enumType).Length; i++)//Populate new Options
         {
              newOptions.Add(new Dropdown.OptionData(Enum.GetName(enumType, i)));
         }
 
         dropdown.ClearOptions();//Clear old options
         dropdown.AddOptions(newOptions);//Add new options
     }
 }

Thank you! This seems to work if I want to create an enum list within this script, but in my other script I already have an enum list, and I want the dropdown on the UI object to be populated with these values, so that when I make a change in the UI, it selects from that list in the script. Maybe I'm thinking about it wrong, but here's an example of what's actually in the script:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 [AddComponentMenu("Color/ColorListener")]
 [RequireComponent(typeof(AudioListener))]
 [ExecuteInEditMode]
 public class ColorListener : MonoBehaviour
 {
     [System.Serializable]
     public enum FormatPresetType
     {
         RGB,
         CMYK
     }
 
     [System.Serializable]
     public enum PatternPresetType
     {
         Black,
         White,
         Red,
         Orange,
         Yellow,
         Blue,
         Custom
     }
 }